This is not unheard of — our female bullsnake, Lucy, and our leucistic Texas rat snake, Snowflake, have done this once or twice — so while we were surprised (February is really out of season for this sort of thing), we were not completely unprepared. Egg binding can be a thing, so we threw together a nesting box full of sphagnum and vermiculite, and then a larger box of sphagnum and vermiculite because her cagemate, Pretzel, wanted to curl up in there as well.

This does explain her recent behaviour: missing the last two or three meals (unheard of for a corn snake, except when gravid), restlessly pacing her cage and upending the furniture (much to the annoyance of Pretzel, who is twice her age and much more seclusive).

Five eggs so far, all infertile — she’s never so much as shared a cage with a male snake, and for good reason: corn snakes are the second-friskiest snake species known to captive husbandry. This is much to the annoyance of the (aptly named) Trouser, the male corn snake who lives in the next cage, who I suspect has been slowly going nuts about living next to two female snakes for years. But when I kept Pretzel and Trouser in the same cage, she would hollow herself out laying eggs that turned out to be infertile. The only surefire way to keep corn snakes from breeding is to segregate them by sex.

All things considered, infertile eggs — or, in the case of live-bearing snakes like garter snakes, egg masses — are a pretty rare occurrence. Caught us off guard this time, it did.

Update, Feb. 17: As of yesterday, LMA has laid an additional six eggs, for a total of eleven. Her backside looks appropriately hollow and she’s entered her post-egg-laying shed cycle, so we can stand down with respect to the risk of egg binding. There’d been some worry about that for a while: at one point it looked like had an egg just above the vent that was not going to pass.